Improper Output Neutralization for Logs Affecting morgan package, versions <1.12.1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published14 Sept 2026
- disclosed11 Sept 2026
- creditiRevivalx
Introduced: 11 Sep 2026
NewCVE-2026-87859 (opens in a new tab)How to fix?
Upgrade morgan to version 1.12.1 or higher.
Overview
morgan is a HTTP request logger middleware for node.js.
Affected versions of this package are vulnerable to Improper Output Neutralization for Logs via the escapeLogField function. An attacker can manipulate log entries by injecting unescaped double quotes into HTTP headers such as User-Agent or Referer, causing log consumers that parse logs by field position to misinterpret attacker-supplied data as subsequent fields.